FASA Games, Inc.

Can caster concentrate on spell in the same round its being cast? Concentration needs Standard Action as Spellcasting Talent do.

So Death Rain(p.289) in the first round will do Step 8 damage, and caster can concentrate in the following round to increse it to WIL+8, or caster if he chooses to is treated as Concentrated in the first round to make dmg test at step WIL+8?

Casting the spell counts as concentration the round the spell is being cast.

In your example, Death Rain would cause Wil+8 on the first round, and will do so as long as the caster maintains concentration. The caster could also do something else, and leave the spell as a lower-powered general AoE damage effect.